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| Titel |
Five years of CO, HCN, C2H6, C2H2, CH3OH, HCOOH and H2CO total columns measured in the Canadian high Arctic |
| VerfasserIn |
C. Viatte, K. Strong, K. A. Walker, J. R. Drummond |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 7, no. 6 ; Nr. 7, no. 6 (2014-06-03), S.1547-1570 |
| Datensatznummer |
250115807
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| Publikation (Nr.) |
 copernicus.org/amt-7-1547-2014.pdf |
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| Zusammenfassung |
We present a five-year time series of seven tropospheric species measured
using a ground-based Fourier transform infrared (FTIR) spectrometer at the
Polar Environment Atmospheric Research Laboratory (PEARL; Eureka, Nunavut,
Canada; 80°05' N, 86°42' W) from 2007 to 2011. Total
columns and temporal variabilities of carbon monoxide (CO), hydrogen cyanide
(HCN) and ethane (C2H6) as well as the first derived total
columns at Eureka of acetylene (C2H2), methanol (CH3OH),
formic acid (HCOOH) and formaldehyde (H2CO) are investigated,
providing a new data set in the sparsely sampled high latitudes.
Total columns are obtained using the SFIT2 retrieval algorithm based on the
optimal estimation method. The microwindows as well as the a priori profiles and
variabilities are selected to optimize the information content of the
retrievals, and error analyses are performed for all seven species. Our
retrievals show good sensitivities in the troposphere. The seasonal
amplitudes of the time series, ranging from 34 to 104%, are captured while
using a single a priori profile for each species. The time series of the CO,
C2H6 and C2H2 total columns at PEARL exhibit strong
seasonal cycles with maxima in winter and minima in summer, in opposite
phase to the HCN, CH3OH, HCOOH and H2CO time series. These cycles
result from the relative contributions of the photochemistry, oxidation and
transport as well as biogenic and biomass burning emissions.
Comparisons of the FTIR partial columns with coincident satellite
measurements by the Atmospheric Chemistry Experiment Fourier Transform
Spectrometer (ACE-FTS) show good agreement. The correlation coefficients and
the slopes range from 0.56 to 0.97 and 0.50 to 3.35, respectively, for the
seven target species.
Our new data set is compared to previous measurements found in the
literature to assess atmospheric budgets of these tropospheric species in
the high Arctic. The CO and C2H6concentrations are consistent
with negative trends observed over the Northern Hemisphere, attributed to
fossil fuel emission decrease. The importance of poleward transport for the
atmospheric budgets of HCN and C2H2 is highlighted. Columns and
variabilities of CH3OH and HCOOH at PEARL are comparable to previous
measurements performed at other remote sites. However, the small columns of
H2CO in early May might reflect its large atmospheric variability and/or the effect of the updated spectroscopic parameters used in our
retrievals. Overall, emissions from biomass burning contribute to the
day-to-day variabilities of the seven tropospheric species observed at Eureka. |
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